US Patent 7406859 - Piezoelectric cantilever rigidity control for AFM

http://www.freepatentsonline.com/7406859.html

Atomic force microscopes are tools which provide researchers the ability to manipulate and inspect individual atoms, molecules, and nanostructures. These tools usually employ cantilevers having a sharp tip combined with a piezoelectric feedback mechanism to regulate the distance between the tip and a sample. However, when choosing rigid cantilever materials for the AFM some sensitivity is lost in the manipulation/detection while less rigid cantilevers are more difficult to control. This patent from Michigan State University teaches a controlled rigidity piezoelectric cantilever which attempts to optimize cantilever performance between rigidity and flexibility. Claim 1 reads:

1. A nanomanipulation system for performing nanomanipulation operations in relation to a sample surface, comprising:

an atomic force microscope having a probe for performing nanomanipulation operations on the sample surface, where the probe includes a cantilever having a layer of piezoelectric material;

a position detector configured to ascertain deformation of the cantilever during a nanomanipulation operation;

an active probe controller adapted to receive data indicative of the deformation from the position detector and implements a control scheme based on the deformation data which maintains rigidity of the cantilever during the nanomanipulation operation, wherein the control scheme produces a control signal that is applied to the piezoelectric material of the cantilever.